Wet ground might have triggered the landslide. And it's possible that the flow was muddy slurry containing about 50 to 60 percent sediment.

"If you have a really sediment-rich [flow], like a very soupy mudflow, the mechanics are very similar to dry, granular flows."

Still, he said, "the simplest model is dry, granular flow."

Rainy Crater

Pelletier noted that his finding involves only the recently created bright streaks.

"This says nothing about water in the Martian past," he said.

In fact, another paper in the same issue of Geology examined the water-related history of Holden Crater, one of six landing sites being considered for the Mars Science Laboratory scheduled to be launched next year.